(1) Field of the Invention
The present invention relates to a system and to a method of inspecting a rotary part to be monitored, the part to be monitored being arranged inside a mechanical member. More particularly, the mechanical member may be a power transmission train, possibly a main gearbox of a vehicle such as an aircraft.
(2) Description of Related Art
Such a main gearbox may be interposed between a power plant and at least one rotor or a rotary shaft of a vehicle. A main gearbox may incorporate at least one speed reduction stage that has at least one rotary part to be monitored. By way of example, such a part to be monitored is provided with a shaft carrying a gear.
The shaft may include segments that are welded to one another. The shaft is likely to wear during its use. A user thus verifies the physical integrity of the rotary part to be monitored, and in particular of the welds of the part to be monitored. In particular, the inspection operation consists in verifying the absence of cracks on the part to be monitored.
However, the part to be monitored is arranged inside the main gearbox, in a zone that is practically inaccessible. It should be understood that it is thus difficult to inspect the part to be monitored in non-destructive manner.
In a first method, an operator removes the main gearbox from the vehicle, then dismantles the MGB. The operator then inspects the part to be monitored using an auxiliary method, e.g. a magnetoscopic test method.
That first method requires the transmission gearbox to be dismantled, which can lead to the main gearbox being out of service for a relatively long period. For a period of about two weeks, for example.
In a second method, an operator drains the main gearbox, and then removes the sump of the main gearbox so as to access the part to be monitored.
The operator then inspects the part to be monitored by inspecting it with a method that uses eddy currents.
That second method may require the main gearbox to be out of service for a moderate duration, e.g. about 8 hours.
The first and second methods are advantageous but they take the mechanical member to be inspected, and consequently also the vehicle having the mechanical member, out of service for a non-negligible duration. Furthermore, those methods present a risk of damaging the parts to be dismantled and/or inspected. The second method also runs the risk of forgetting a part inside the main gearbox.
The Japanese document published under reference 07-174739, on Jul. 14, 1995, describes a device that is provided with a carriage carrying a plurality of probes. Springs press the probes against the surface of the part to be monitored.
Document KR 2010 0078441 describes a method of inspecting an axle by ultrasound. The method implements a system including, in particular, a detection device, a device for removing oil, and a device for feeding oil.
Document EP 2 192 406 describes copying apparatus provided with a carriage carrying a flaw detector for detecting flaws by ultrasound.
Ultrasound probes may thus be used for attempting to detect flaws. Such a probe emits a signal towards the part to be monitored. As a function of the echo received in return by the probe, an operator can determine whether a part presents a flaw. The echo may also convey other information, e.g. relating to a change in the shape of a part.
Any flaw and information deduced from the echo is referred to below as a “flaw” for convenience.
However, it can be difficult to use such a probe. Specifically, the probe should cause waves to propagate in constant manner relative to the part to be monitored, in order to provide information that is usable.
In addition, by way of information and in a field that is unrelated to the invention, a device is known for treating prostate cancer by ultrasound. A probe emits ultrasound waves for treating a prostate. The probe may be arranged on the end of an endoscope. The end may present a shape that is concave around the probe, so as to avoid dispersing the emitted waves.
The device does not provide any teaching for detecting a flaw on an internal rotary part of a mechanical member.
Internet address http://www.olympus-ims.com/fr/erw/ describes an inspection system for inspecting tubes that are electrical resistance welded. That system uses multi-element ultrasound technology for inspecting a weld by means of a rotating head. The ability of the head to rotate allows each probe to move independently from −120° to 120° along the weld to be inspected.
Documents US 2006/162456, US 2012/167688, US 2008/312848, WO 2011/004101, and EP 2 042 076 are remote from the invention.
Document US 2006/162456 describes a system for inspecting a stationary stringer. That system presents an instrument that is trapezoidal.
Document US 2012/167688 presents a device that is fastened in permanent manner to a tube so as to inspect its thickness.
Document US 2008/312848 describes a system that is provided with lugs and with a probe.
Document WO 2011/004101 presents a device for inserting into an endoscope orifice. The device includes a stick carrying a pivotable finger. The pivotable finger extends from an end provided with a probe-support blade to an end carrying a movable bearing skid.
Document EP 2 042 076 presents a steerable endoscope.